A cleanup of an oil spill along Vietnam's central coast has nearly restored the region's beaches to their normal condition, but the source of the spill remains a mystery, authorities said Tuesday.
The amount of oil washing ashore appears to be decreasing, said Nguyen Viet Hung, an official at the Thua Thien Hue provincial natural resources and environment department, the AP says.
"The beaches are cleaner today," Hung said. "But we have told residents and soldiers to remain posted on the coast to collect new chunks of oil as they wash ashore."
Authorities are continuing to search for the source of the spill, which blackened some of Vietnam's premier tourist beaches, said Nguyen Doan Chat, an official from Vietnam's national search and rescue committee, the AP reports.
Authorities have been surveying the area by helicopter and are testing the oil to determine whether it is crude or refined, which might help in identifying its source.
"The oil probably came from somewhere very far offshore," Chat said.
The oil has washed ashore in the provinces of Danang, Quang Nam, Thua Thien Hue and Quang Tri.